3 Phase Power- Any reason not to?

[pamike]

I am in the process of design/build of a new barn/shop. Building will have an all new electric service. I talked to the power company and they said 3 phase in available, and they can set the pole and provide power at no cost, which is the same as single phase. Is there any reason I WOULDNT want to do three phase? I know surplus 3 phase equipment, such as welders can be found way cheaper than traditional single phase machines. The only down side I can think of is that commercial 3 phase power has a flat charge on top of your kilowatt charge...

 

[Rookie2]

Don't take this the wrong way....but if you don't have a business need or 3ph equipment sitting there stay away. If your making a living from a shop and want to add more equipment then it may be beneficial . IMO

read this :

http://www.garagejournal.com/forum/showthread.php?t=304761

 

[Stuart in MN]

Three phase power is generally only available for commercial accounts, so talk to your utility about how much it will actually cost per month - with that monthly charge on top of the kilowatt-hours it can be pretty expensive.

 

[Hpozzuoli]

I run 3 phase at my laundromats. The machines are cheaper than single phase. you also have more power coming in to run larger equipment. That's all I got.

 

[dw1]

I know it would be a one time cost, but the last 3 phase 200 amp MB panel I bought was about $600, as stated above, you might want to get a close estimate on what your monthly bill will run. If it costs you nothing upfront, you are lucky, they would have 3 times the initial investment, around here all they are concerned with is how long it will take them to recoup their investment.
Good Luck!
What size service are you talking about, if you go "Big" you could end up with a CT cabinet and CT's, Power Blocks and then you are getting into some $$$

 

[theoldwizard1]

3 phase "Y" you can pull 120V off each leg, but only 208V off of any 2 legs. This is a problem if you have any 240V statioanry equipment.

3 phase "delta" can only deliver 120V IF you have a neutral "tap" and that is only on one leg.

The only thing I ever wired was "Y". Very simple.

 

[pamike]

I do want to price out a panel cause that might be a big increase in cost. Not sure on the size of the service. 200 amps is probably plenty for me. Because this bulding isnt at my home it is automatically commercial, so just a matter of whether I pay the commercial rate of 3 phase or single phase.
I just like the idea of being able to power just about anything. Find a welder at a sale that 3 phase and sells cheap, no problem I can run it...
I work with 3 phase at work and much prefer it over single phase. Motors are easy to wire, no issue with direction on spin, etc.
As far as VFD's. If you have a motor starter many 3 phase motors run fine without a VFD. Correct? I may be wrong on this but I think thats the case..

Oldwizard- What size single phase stuff would I have trouble with if I had 3 phase "Y"? 5 HP motors?

 

[wyliesdiesels]

Not only do u have to pay the monthly/meter fee and the Kwh usage but u MAY also have to pay a demand charge and TOU(time of use)/peak and off peak Kwh rates.

3-phase electricity aint cheap.

Also, there is several flavors of 3-phase and u need to know the differeneces and cautions about each.

3 phase "Y" you can pull 120V off each leg, but only 208V off of any 2 legs. This is a problem if you have any 240V statioanry equipment.

3 phase "delta" can only deliver 120V IF you have a neutral "tap" and that is only on one leg.

The only thing I ever wired was "Y". Very simple.

U can use 240v machines with 208v Y service by utilizing buck boost transformers.

And 240vD/120v has 2 useable 120v legs....

I do want to price out a panel cause that might be a big increase in cost. Not sure on the size of the service. 200 amps is probably plenty for me. Because this bulding isnt at my home it is automatically commercial, so just a matter of whether I pay the commercial rate of 3 phase or single phase.
I just like the idea of being able to power just about anything. Find a welder at a sale that 3 phase and sells cheap, no problem I can run it...
I work with 3 phase at work and much prefer it over single phase. Motors are easy to wire, no issue with direction on spin, etc.
As far as VFD's. If you have a motor starter many 3 phase motors run fine without a VFD. Correct? I may be wrong on this but I think thats the case..

Oldwizard- What size single phase stuff would I have trouble with if I had 3 phase "Y"? 5 HP motors?

If u need more than 400a, u would need a CT cabinet and meter base.

A motor starter doesn't replace a VFD. VFDs are for changing and controlling the speed of the motor. If u dont need variable speeds then u would use a starter. If u use a VFD then u dont need a motor starter.

And Im not sure what u mean by "trouble with". Many motors are designed to run on 208v. But it really depends on what type of 3-phase service u get.

 

[KenC]

Not only do u have to pay the monthly/meter fee and the Kwh usage but u also have to pay a demand charge and TOU(time of use)/peak and off peak Kwh rates.

3-phase electricity aint cheap.

Also, there is several flavors of 3-phase and u need to know the differeneces and cautions about each.

,

e service u get.

The quote in red above is NOT universally true. I have 240v delta in my shop, no premium cost of any kind over single phase 240 in my city.

the OP just needs to be sure of the facts before signing up.

I was even lucky enough to acquire a used panel full of breakers for a whole $10 at an auction. And, the city utility installed the extra wire from the street and transformer at no charge. I was replacing an existing 1phase service due to a main breaker failure and wanted to upgrade.

 

[theoldwizard1]

Oldwizard- What size single phase stuff would I have trouble with if I had 3 phase "Y"? 5 HP motors?

The biggest problem you will run into with large single loads is phase imbalance. Depending on the service you have from the POCO, you could be charged extra for that imbalance.

That fact that you are even THINKING about running a single phase motor means you do not understand the benefits of 3 phase. What you should be asking how much is it going to cost me to change that motor to a 3 phase motor.

Even a 1/2-1 hp furnace blower motor runs more efficiently on 3 phase.

 

[wyliesdiesels]

With 3-phase wye the imbalance is carried by the neutral...

The quote in red above is NOT universally true. I have 240v delta in my shop, no premium cost of any kind over single phase 240 in my city.

the OP just needs to be sure of the facts before signing up.

I was even lucky enough to acquire a used panel full of breakers for a whole $10 at an auction. And, the city utility installed the extra wire from the street and transformer at no charge. I was replacing an existing 1phase service due to a main breaker failure and wanted to upgrade.

Yes i forgot the keyword MAY...

Where do u live?

Youre lucky.

PoCos in California charge every single thing they can!

 

[sberry]

A lot to go thru so a guy can score an obsolete welder.

 

[pamike]

A lot to go thru so a guy can score an obsolete welder.

Most of the large high capacity welders are 3 phase...not sure what is obsolete about 3 phase.

I am going to call the power company today to confirm what the engineer told me, but from what he said I just have to pay a surcharge on my useage...

 

[woodzy]

If that was available in my area for free, I would be all over it. I have 9 machines that run on three phase and run them off a 10 HP phase converter. You can't beat true three phase if you need it and can get it.

 

[ovrrdrive]

A lot to go thru so a guy can score an obsolete welder.

I believe all of the major welder manufacturers still make 3ph welders. I know Miller does. What's obsolete about a brand new welder that will do 400A at 100% duty?

 

[pamike]

If that was available in my area for free, I would be all over it. I have 9 machines that run on three phase and run them off a 10 HP phase converter. You can't beat true three phase if you need it and can get it.

My thoughts exactly. PLUS, a lot of hobby guys CANT get 3 phase so when there is 3 phase equipment on the market the buyers are limited. I have seen a lot of used 3 phase equipment sell cheap. 10 year old welders that a big plant replaced, air compressors, grinders, the list goes on and on...

 

[Rookie2]

Here is some more reading ! Your in the First Energy Cloud !
1) read about Act-129 in Pa. on their site.
2) call your POCO's office and ask to have an explanation on billing using a DEMAND Watt meter. You will get one . YOU pay in tiers like the old pay phones.
3) go ask around ,small shops/garages find a small business in an industrial park.



http://www.garagejournal.com/forum/showthread.php?t=293119&page=2

Peace OUT !

 

[KenC]

With 3-phase wye the imbalance is carried by the neutral...



Yes i forgot the keyword MAY...

Where do u live?

Youre lucky.

PoCos in California charge every single thing they can!

I'm in NE Oklahoma, in a smaller city and our electric and water is city owned and operated.

Others near me are served by either a rural coop or larger company and aren't as lucky!

I was even able to pull a permit and do my own panel swap!

 

[theoldwizard1]

The real benefit of 3 phase is lower cost to OPERATE motors ! That is why mills and lathes that were meant to run a large number of hours per day use 3 phase motors.

A welder would really only benefit from 3 phase for a couple of reasons. A) you need extremely high output current or (more likely) B) you need continuous operation. There are not that many welders designed to run 100% duty cycle.

 

[sberry]

This is kind of what I was getting at. What is the intent here? If it is to get deals on old tools, you can get the power for cheap then its a deal. What I meant by obsolete is that is the intent and is there a need for a 400A welder? This has been a limiting factor for me, I live rural, in hindsight it may not have been a bad thing as I would have spun off dragging home stuff I had no real use for.
I got a bud been collecting and building machine tools so he can build more tools. Its as fine a hobby as any but he has no use for any of it other than me sliding in a couple times a year to do a little job. We get cutters, then need a way to sharpen them and its all great if there is end use.
All the great use stuff has got smaller and lighter, small mig, inverter welders and battery power tools. So much less is made the old way in job or machine shops, while there is a place for it all it can become something unto its own.
I used to machine a few things, today in general auto and property maintenance almost never. Lotso little welds and steel mods and hand drilling of holes, its a rare day I use a drill press.

 

[sberry]

If I was going to open a real weld or machine shop would definitely want it. (5 hp comp really doesn't count) Using it on small motors on machines comes that way is great but wish I had it for large motors.

 

[zkling]

I believe all of the major welder manufacturers still make 3ph welders. I know Miller does. What's obsolete about a brand new welder that will do 400A at 100% duty?

They do, but the thing is, IMHO, if a person truly had the need for one of those machines, they wouldn't be asking in the first place if they should be getting 3ph or not. Their needs would make that decision for them.

I am in the process of design/build of a new barn/shop. Building will have an all new electric service. I talked to the power company and they said 3 phase in available, and they can set the pole and provide power at no cost, which is the same as single phase. Is there any reason I WOULDNT want to do three phase? I know surplus 3 phase equipment, such as welders can be found way cheaper than traditional single phase machines. The only down side I can think of is that commercial 3 phase power has a flat charge on top of your kilowatt charge...

I would just ask yourself what do you plan on doing in this shop and what all equipment will you have. Realistically. As others have mentioned you need to talk to your power company and see what all charges will go along with the added service. Break it down to a per month cost and determine if that cost is worth it to you or not.

 

[LutzTD]

most of the welders convert from single the three phase by swapping jumpers anyway, so thats no biggy.

I looked at it for my shop as I have several machines that require 3 phase. But he 3 phase power distribution equipment is expensive, you cant just go get a breaker from home depot when you want one. Used market is cheaper if you got the time to wait. I didnt know anything about distributing the three phase so there is a learning curve.

In the end, I used a VFD for the three phase band saw to get speed control, I used VFD for my small bridgeport for the same reason. I built a phase converter that works for my lathes, the punch press, surface grinder and the big drill press I have. Even with all of the conversion equipment its still way cheaper than distributing the three phase for mostly lights and 120V stuff anyway.

 

[zkling]

most of the welders convert from single the three phase by swapping jumpers anyway, so thats no biggy.

I looked at it for my shop as I have several machines that require 3 phase. But he 3 phase power distribution equipment is expensive, you cant just go get a breaker from home depot when you want one. Used market is cheaper if you got the time to wait. I didnt know anything about distributing the three phase so there is a learning curve.

In the end, I used a VFD for the three phase band saw to get speed control, I used VFD for my small bridgeport for the same reason. I built a phase converter that works for my lathes, the punch press, surface grinder and the big drill press I have. Even with all of the conversion equipment its still way cheaper than distributing the three phase for mostly lights and 120V stuff anyway.

Yes and no, most of the newer machines will run on both single and 3 phase but the single phase output is a bit less than the 3 phase supplied output.

Alot of the common older machines, that are still being serviced and what not were primarily single phase. Getting 3 phase just so one can get an ancient mig machine or the like is a poor choice IMHO.

Now if this guy plans on having a few machining centers in his pole barn that would be a different story, but again, since the question was asked in the first place I kinda doubt that is the case.

 

[LutzTD]

Yes and no, most of the newer machines will run on both single and 3 phase but the single phase output is a bit less than the 3 phase supplied output.

Alot of the common older machines, that are still being serviced and what not were primarily single phase. Getting 3 phase just so one can get an ancient mig machine or the like is a poor choice.

the synchrowave I had and the aerowave I have now can both be converted to either. So at least for the millers I would want it is true

 

[zkling]

the synchrowave I had and the aerowave I have now can both be converted to either. So at least for the millers I would want it is true

I'm ~99% sure the syncrowave has always been and always will be a single phase machine.

I suppose I should add, when I referenced "newer machines" I was speaking of inverted based machines.

 

[LutzTD]

I'm ~99% sure the syncrowave has always been and always will be a single phase machine.

I suppose I should add, when I referenced "newer machines" I was speaking of inverted based machines.

yeah, I was wrong, thought it was both but it was just the aerowave.

 

[Handyfarmer]

I know I am some what late to the party here,

but I have thee phase open leg delta on the farm, most of the farm is single phase 240 volt, and the shop is currently the only place I have three phase (besides the transfer switch), I do plan on putting three phase in the wood shop,

the delta or open delta is used when the load is low on the three phase side and and the majority of the loads are single phase,

in the shop I put in a three phase box and have the original single phase box, (I bought the three phase box and breakers off Ebay,

I have in three phase, mill, and lathe, air 5 hp, compressor, a walk in freezer and cooler and will put in a shop door opener, before I use a rotary converter,

If you can get it put in for low cost I sure would consider it, for a small shop the delta is (IMO) the way to go, you have the best of single phase and three phase,

one can buy three phase motors for a fraction of single phase, and if you have an interest in industrial equipment of any type most of it is three phase and is sold many times for penny's on the dollar do to the fact there three phase,

my electrical rates are the same as if it was just the farm on single phase with a home rate, and if your a power user many times there less,,

 

[nsula_country]

If u need more than 400a, u would need a CT cabinet and meter base.

Not 100% true... I recently found out our POCO offers 600A shunt meters. No CT's. It's like 12" long! I've installed a 600A, 480v 3P meter base. It's massive!

CT

 

[yyc_ranger_4x4]

Wow...open leg delta wiring. That's not something I've heard about since theory classes in my apprenticeship classes. LOL

 

[Steve from Socal]

Open Delta is still somewhat common in rural areas. I agree this would be your most economical set up if available. Ag three phase may not have demand but, most industrial does.

I have 480 three phase and with demand I pay an average of 400.00 a month. I have a number of 20-30HP machines that run infrequently, my 25 HP mill, 20HP lathe and, 600 amp welder are the main big consumers. I use these perhaps 6~8 hours a week. My XMT 450 is a three phase welder, it could run on single phase at 1.73 times the amperage on three phase, 240 single phase that is 115 amps!

Depending on your power requirements a phase converter could be a better strategy.

Steve

 

[malibu101]

Not 100% true... I recently found out our POCO offers 600A shunt meters. No CT's. It's like 12" long! I've installed a 600A, 480v 3P meter base. It's massive!

CT

I think it depends on the local utility company. (POCO)
I have seen recent installs of 400A 120/208Y meters. Yeah, they're big.
But the step to 600A 120/208Y has a large CT cabinet since, for many years, my local utility company does not do open air CT's.

 

[Lightman]

I think it depends on the local utility company. (POCO)
I have seen recent installs of 400A 120/208Y meters. Yeah, they're big.
But the step to 600A 120/208Y has a large CT cabinet since, for many years, my local utility company does not do open air CT's.

ck on the NEMA form numbers for the diffrent meter applications.

15/16S for appliactions up to 200 amp ( also 320 amp rating meters, various voltages) Think the 400 amp meter bases are for the 320 amp contnious meters, vs the normal 200 amp meter
look up 15/16K meter. 600 amp rating, 480 amp continious, meter can be bought for for voltage, 120/208v ,120/240v, 277/480v.
Former po co operations guy who worked with meters ( and smart meters) a bunch.

 

[wyliesdiesels]

Not 100% true... I recently found out our POCO offers 600A shunt meters. No CT's. It's like 12" long! I've installed a 600A, 480v 3P meter base. It's massive!

CT

The PoCos I have experience with havent used shunt metering as long as Ive been in the business.

And one of them has had CTs for decades, long before i got into the electrical field.

I was just looking at an old corner grounded delta service with open air CTs(only 2) mounted on the pole cross bar for a 480v Delta service. The metering equipment is in a large panel box mounted at eye level between the 2 H Frame telephone poles. This service has to be from the 60s.

I have NEVER seen shunt metering in the field.

As far as open delta service, MID and PG&E will no longer install new open delta service. But we have quite a few existing open delta services...One glance at the pole and u can tell its open delta because theres only 2 cans.

 

[nsula_country]

The PoCos I have experience with havent used shunt metering as long as Ive been in the business.

And one of them has had CTs for decades, long before i got into the electrical field.

I was just looking at an old corner grounded delta service with open air CTs(only 2) mounted on the pole cross bar for a 480v Delta service. The metering equipment is in a large panel box mounted at eye level between the 2 H Frame telephone poles. This service has to be from the 60s.

I have NEVER seen shunt metering in the field.

As far as open delta service, MID and PG&E will no longer install new open delta service. But we have quite a few existing open delta services...One glance at the pole and u can tell its open delta because theres only 2 cans.

I did not mean "shunt" like you are thinking... Poor description on my part.

I meant an inline meter @ 600a, 480v. Internal shunted meter. No CT cabinet. It is a massive meter! We set the service up for CT's. When POCO came out they said CT's were only required for above 600a and provided the can. Learn something new every day.

CT

 

[wyliesdiesels]

O I c.

U got a pic?

Yeah over 400a around here is CTs.

I dont like feed thru 480v meters. Seen several that blew up.

 

[nsula_country]

O I c.

U got a pic?

Yeah over 400a around here is CTs.

I dont like feed thru 480v meters. Seen several that blew up.

If I cannot find a pic (I took some) I'll drive by. It's not far out of town. But it was memorable.

CT

 

[Lightman]

http://www.landisgyr.com/webfoo/wp-content/uploads/product-files/LG_kbase_brochure_092506_FINAL.pdf

All meters at my coop were changed to smart metering so we removed all of the old electromechanical to install electronic metering with communication modules. single phase and three phase.
When possible used the K4 and K7 meter can instead of the CT set, less labor and material $ to install and maintain.